/*
Copyright (c) 2024, Shanghai Iluvatar CoreX Semiconductor Co., Ltd.
All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License"); you may
not use this file except in compliance with the License. You may obtain
a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package dl

import (
	"fmt"
	"unsafe"
)

// #cgo LDFLAGS: -ldl
// #include <dlfcn.h>
// #include <stdlib.h>
import "C"

const (
	RTLD_LAZY     = C.RTLD_LAZY
	RTLD_NOW      = C.RTLD_NOW
	RTLD_GLOBAL   = C.RTLD_GLOBAL
	RTLD_LOCAL    = C.RTLD_LOCAL
	RTLD_NODELETE = C.RTLD_NODELETE
	RTLD_NOLOAD   = C.RTLD_NOLOAD
	RTLD_DEEPBIND = C.RTLD_DEEPBIND
)

type DynamicLibrary struct {
	Name   string
	Flags  int
	handle unsafe.Pointer
}

func New(name string, flags int) *DynamicLibrary {
	return &DynamicLibrary{
		Name:   name,
		Flags:  flags,
		handle: nil,
	}
}

func (dl *DynamicLibrary) Open() error {
	name := C.CString(dl.Name)
	defer C.free(unsafe.Pointer(name))

	handle := C.dlopen(name, C.int(dl.Flags))
	if handle == C.NULL {
		return fmt.Errorf("%s", C.GoString(C.dlerror()))
	}
	dl.handle = handle
	return nil
}

func (dl *DynamicLibrary) Close() error {
	err := C.dlclose(dl.handle)
	if err != 0 {
		return fmt.Errorf("%s", C.GoString(C.dlerror()))
	}
	return nil
}

func (dl *DynamicLibrary) Lookup(symbol string) error {
	sym := C.CString(symbol)
	defer C.free(unsafe.Pointer(sym))

	C.dlerror() // Clear out any previous errors
	C.dlsym(dl.handle, sym)
	err := C.dlerror()
	if unsafe.Pointer(err) == C.NULL {
		return nil
	}
	return fmt.Errorf("%s", C.GoString(err))
}
